The distributor does what one imagines under. I run the distribution on my Speedport 921V router with only one ISDN input. Now have my telephone system and my ISDN Fritz Card from the PC to the distributor and then connected to the Speedport. Everything works fine. PBX shares further to the discussions and from the PC, I can now once again directly send and receive faxes, ... at the same time and without problems.
So fully satisfied for and recommended !!! THANK YOU